1. Field of the Invention
This invention is related generally to resonant transformer circuits designed to generate high voltage pulses for such applications as linear induction accelerators, electromagnetic launchers, and particle beam accelerators.
2. Description of the Prior Art
In pulse power applications, the object of the designers is to place the maximum amount of voltage on the load capacitors with a high energy transfer efficiency. Author G. J. Rohwein, in his paper, "A Three Mega-volt Transformer for PFL Pulse Charging", published in IEEE Transactions, Nuclear Science NS-26, 4211, 1979, introduced a transformer designed to operate in a dual resonance mode. The open circuit resonant frequencies of the primary and secondary transformer circuits are equal, and transformer coupling efficiency is 0.6. In this circuit, the coupling of the energy, neglecting dampening, takes place from C.sub.1 to C.sub.2. The concept of the dual resonant transformer circuit has been known since at least 1966, (see David Finkelstein, Philip Goldberg, and Joshua Suchatowitz, "High Voltage Impulse System", The Review of Scientific Instruments, vol. 37, p. 159 (1966)). Operation in the dual resonant mode has several disadvantages. First, the transformer acts as a pulse line with a different impedance from the actual pulse line, introducing an after pulse as the internal capacitance of the transformer discharges into the pulse line; and second, fault modes in the pulse line can produce dangerous high voltage spikes on the transformer's secondary. These disadvantages are commonly removed by the introduction of an external inductor to provide isolation between the pulse line and the transformer. However, the circuit does not couple 100% of the available energy into the pulse line. The remaining energy tends to ring in the transformer. Such ringing is undesirable because repeated undampened voltage reversals have a deleterious effect on transformer lifetime and insulation strength.
In a paper described by K. A. Zheltov, A. V. Malygin, M. G. Plickin, and V. F. Shalimanov entitled, "Miniature Voltage Pulse Generator For Sub-Nanosecond Electron Accelerators", Instruments and Experimental Techniques, Vol. 26, page 589, 1983, a resonant pulse generator circuit was disclosed, but did not address the problem of generating high energy transfer.